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shminux comments on The Fabric of Real Things - Less Wrong
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The lightspeed limit is a local notion. Something whizzing by you cannot be clocked to travel at or faster than light, but there is no clear definition of the relative velocity of two spatially separated objects in a curved spacetime.
I don't suppose you have a link to a reasonably accessible explanation of this point?
Maybe this will help... It's not overly accurate, but seems to be accessible enough.
Putting this here to help passers-by. My basic confusion appears to have been caused by not realizing that the universe is stretching. Thus, we aren't in an inertial frame with respect to other galaxies.
Inertial frame is a local notion, as well, so "inertial frame with respect to other galaxies" is not a meaningful statement. In GR inertial frame is generalized to a geodesic. There is also the concept of comoving frame, that in which the expansion rate looks the same in all directions.
I'm afraid the links I've seen are all actually less accessible than shminux's explanation.